Fixed #29606 -- Added type check for ALLOWED_HOSTS setting.

[AdamDonna]

Literally just the same as other people have pushed up but having made changes for feedback that wasn't addressed. #13927

I attempted to contribute to the existing fix but there were permission issues

[AdamDonna]

@felixxm This is ready for another review - the test failure was just a flaky test

[AdamDonna]

@tim-mccurrach This is ready for another review - I think it's addressing all the feedback across all the PRs now

[tim-mccurrach]

@AdamDonna
Looks good, just a few small changes requested.

Also, this PR should be a single commit. If you're able to, squash these commits to a single commit and then force push it.

[AdamDonna]

Also, this PR should be a single commit. If you're able to, squash these commits to a single commit and then force push it.

Great. I've fixed up the last comments, then squashed. 👍

[felixxm]

@AdamDonna Thanks for updates 👍 However I don't think we need a separate system check, it should be enough to add 'ALLOWED_HOSTS' to the tuple_settings (see Tim's comment):

diff --git a/django/conf/__init__.py b/django/conf/__init__.py
index 03bf923bb2..3f387a5ffc 100644
--- a/django/conf/__init__.py
+++ b/django/conf/__init__.py
@@ -141,6 +141,7 @@ class Settings:
         mod = importlib.import_module(self.SETTINGS_MODULE)
 
         tuple_settings = (
+            "ALLOWED_HOSTS",
             "INSTALLED_APPS",
             "TEMPLATE_DIRS",
             "LOCALE_PATHS",

Checking types of elements it's not crucial, IMO.

[AdamDonna]

@felixxm @tim-mccurrach Thanks for your work on this so far. I've revised the implementation to be more in keeping with Tim's comment. Does any documentation need to change as a result of this?

[felixxm]

@AdamDonna Thanks 👍 Docs changes are not needed.

[felixxm]

I added msg to tests.